(1) Field of the Invention
The present invention relates generally to electrically actuated stepping motors, and more particularly to a stepping motor having a rotor angled with respect to its output shaft.
(2) Prior Art
In my copending U.S. Patent Application Ser. No. 83,339, filed Oct. 10, 1979, there is shown a wave generator having two or three lobes as part of a motion transmitting mechanism. The wave generator acts upon a flexspline gear which in one particular embodiment, transmits rotary power to an output shaft. Motion transmission in motors is also embodied in U.S. Pat. No. 3,331,974, to Proctor, wherein a deflectable rotor with spline teeth near one end thereof engages a circular spline in two diametrically opposed areas to effectuate rotary motion therebetween. The rotor, however, uses a magnetic shim stock wound therewithin, and a radial deflection stress is induced in the rotor, which stress limits the number of steps per output shaft revolution.
Subsequent stepping motor development is shown in U.S. Pat. No. 3,456,139 to Newell; U.S. Pat. No. 3,492,151 to Foskett; U.S. Pat. No. 3,644,764 to Newell and U.S. Pat. No. 3,894,255 to Newton, which each describe stepping motors utilizing some form of a single lobed rotor. They also each use a universal joint which secures a nutating gear or drum-like rotor to an output shaft. This type of junction is however, subject to fretting and may break down prematurely. The U.S. Pat. No. 3,456,139 to Newell shows a double wobble drum arranged about a universal ball joint. The U.S. Pat. No. 3,492,515 to Foskett discloses a face gear biasedly arranged on a spheroidal member by a spring. The U.S. Pat. No. 3,644,764 to Newell also shows a face gear with two sets of associated gear teeth arranged on a universal joint on an output shaft. The U.S. Pat. No. 3,894,255 to Newton shows a single lobed motor with a drum-like rotor adapted with a universal joint near one end, and an extended shaft adapted to a gear with a tip that gyrates about a similar stationary tip in an end bell. This arrangement is complicated in its support and its drive functions in accomplishing its objective.
It is an object of the present invention to provide a single lobed stepping motor of less complicated construction than is shown in the prior art.
It is a further object of the present invention to provide stepping motors wherein internal and external gears could be easily assembled, with teeth of differing numbers, to produce a variety of ratios therewith.
It is a still further object of the present invention to provide a stepping motor wherein the rotor is radially attached to the stator.
It is yet a further object of the present invention to provide a stepping motor having a rotor attached to an output shaft by a deflectable diaphragm capable of outperforming the prior art stepping motors in efficiency, range of operation and economy.